Head gaskets are generally known that have a sealing bead for sealing the interface between a cylinder head and a cylinder of an engine. Such gaskets, however, may disadvantageously introduce crevice volume to the combustion chamber defined by the cylinder. More specifically, known head gaskets extend only partially across the mating surfaces of the cylinder head and cylinder, thereby introducing an annular shaped crevice volume extending outwardly from a combustion chamber to the inner diameter of the gasket. Crevice volume is a source of unburned hydrocarbons that are subject to control by emissions regulations, and therefore reduction of crevice volume may be advantageous.
While the goal of reducing crevice volume may appear straightforward, some applications require additional considerations that prevent the use of known solutions. In smaller engines where the cylinder is formed directly in an engine block, for example, it is known to reduce the diameter of the sealing bead to substantially match the diameter of the combustion chamber, thereby reducing the crevice volume. This approach, however, is not applicable engines having top flange cylinder liners that are inserted into the engine block, as the load path when assembled extends from the cylinder head, through the sealing bead of the gasket, into the flange of the cylinder liner, and finally to the block. As a result, the sealing bead of a gasket used with a top flange cylinder liner must be aligned with the cylinder liner flange to avoid generating excess stress and bending moments. The cylinder liner flange is larger than the cylinder bore diameter, and therefore it is not possible to reduce the sealing bead diameter to reduce crevice volume without introducing undesirable stress and bending of the liner.